"Friday," the concluding chapter, celebrates the transition into fall, a new season, one to which Thoreau attributes qualities of regeneration rather than decline. He refers to the Concord Cattle Show, a seasonal festival of nature parallel to the great celebrations of antiquity. He discusses genius; the fact that genius and popular appreciation have nothing to do with one another; the poet — who possesses God within — and his rough, natural, truthful, penetrating strength; and the greatness of an artist, which lies in the degree to which his work expresses his life. He writes of the poet Ossian, of perspective and perception, of seeing things anew, and of permanence over the lapse of time. The "constant abrasion and decay of our lives" are presented as imparting new life — making "the soil of our future growth" — and the unity of body and spirit is restated.
Thoreau turns to mathematics and science, asserting that natural law, scientific truth, and moral law should not be considered separately from one another. He complains that the man of science does not approach the "central facts." Science will not be elevated until the scientist adopts a broader vision. Following qualified praise of Chaucer, Thoreau laments the decline of poetry from a ruder, more natural time, and discusses poets and poetry. He identifies two types of poets. One cultivates life, the other art. The former possesses genius and inspiration, the latter intellect and taste. He focuses again on the rough vigor of the work of genius. He returns to the river, and to nature's composition of an autumnal poem. Autumn is presented as a time of inner verdure and regeneration, possessing "ripe fruit" behind the sheaves and under the sod.
Thoreau urges man to spiritualize and naturalize so as to be open to the beauty of the world and to aspire to immortal existence, to conceive of a "better heaven." Temporal morality, he says, is petty beside pure, primeval nature. The seeking of nature beyond the ordinary is comparable to the discovery by Columbus of the New World. Thoreau metaphorically suggests that the world has many rings, that we live on the outermost, and that we must travel to the core. He urges the examination not of what was, but of what is, and optimistically states his hope that he will gain information on the "OTHER WORLD." Both science and poetry are "particles of information"; poets, philosophers, and spiritual men are "our astronomers." Thoreau advocates a radical, intuitive, expansive kind of thought, as opposed to a commonsensical, logical, narrow one. He points out the distance between what is and what appears to be. He quotes from Oriental literature on immortality and refers to the ways in which nature makes use of us without our knowledge (for instance, in the unintentional scattering of seeds as we walk). The book ends with a discussion of silence — presented as the ultimate refuge, a waiting for sound, and an openness to revelation. Thoreau refers indirectly to his hopes for his own earnest, reflective, suggestive book. And so the two travelers return to Concord, completing the circle of their journey.
